This study evaluated long-term clinical and radiologic results of Dunn's osteotomy carried out in 50 consecutive cases for severe slipped capital femoral epiphysis. The results of all the patients were analyzed with 4 years 6 months of follow-up. The clinical results were very good and good in 90% of the patients and were fair or poor in 10% of the patients. Seven patients had an important complication (total necrosis or chondrolysis), and the clinical evolution was studied. Dunn's procedure seems to be adequate to correct severe slips.